Implementation of Metal Casting Best Practices - EERE - U.S. ...

Sprue - Metal that fills the conical passage (sprue hole) that connects the nozzle or hot chamber
to the runners of a hot chamber machine. 102
Stack Melter - A type of melting furnace where the metal is charged, preheated, and melted in
the exhaust. Also referred to as a tower or shaft melter. 103
Tundish - A reservoir in the top part of a mold into which molten metal is poured. 104
Tuyere - An opening through which the air blast enters the cupola (or a blast furnace, or any
other vessel).
V-process - A molding process, developed in Japan, in which the mold is formed by stretching a
sheet of Mylar plastic over a heated metal pattern so that it conforms to the shape of the pattern.
A box of loose sand is placed over the pattern, and a vacuum is applied to the sand, which then
conforms to the shape of the Mylar film. Thus supported, the sand-backed film is removed from
the pattern and is used as one part of mold. When the metal is poured, the vacuum is released,
and the loose sand falls away from the casting. 105
Vacuum Casting - A process of casting that uses a vacuum to draw molten metal into a mold. 106
Yield - In production of castings, a value expressed as a percentage indicating the relationship of
the weight of a casting and its gating system. For example, if the casting and gating system
weigh 125 lb. and the casting weighs 100 lb., the yield is 80%. 107
Zinc casting alloys - Alloys that are well suited for connectors and other electronic components
due to good electrical conductivity, which ranges from 25 to 27% IACS (International Annealed
Copper Standard). Zinc alloys have electrical conductivity properties similar to those of
aluminum casting alloys and are superior to brass, magnesium and cast iron. 108
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